PMID- 10574788
OWN - NLM
STAT- MEDLINE
DCOM- 19991214
LR  - 20190915
IS  - 0969-2126 (Print)
IS  - 0969-2126 (Linking)
VI  - 7
IP  - 11
DP  - 1999 Nov 15
TI  - The pre-hydrolysis state of p21(ras) in complex with GTP: new insights into the
      role of water molecules in the GTP hydrolysis reaction of ras-like proteins.
PG  - 1311-24
AB  - BACKGROUND: In numerous biological events the hydrolysis of guanine triphosphate 
      (GTP) is a trigger to switch from the active to the inactive protein form. In
      spite of the availability of several high-resolution crystal structures, the
      details of the mechanism of nucleotide hydrolysis by GTPases are still unclear.
      This is partly because the structures of the proteins in their active states had 
      to be determined in the presence of non-hydrolyzable GTP analogues (e.g. GppNHp).
      Knowledge of the structure of the true Michaelis complex might provide additional
      insights into the intrinsic protein hydrolysis mechanism of GTP and related
      nucleotides. RESULTS: The structure of the complex formed between p21(ras) and
      GTP has been determined by X-ray diffraction at 1.6 A using a combination of
      photolysis of an inactive GTP precursor (caged GTP) and rapid freezing (100K).
      The structure of this complex differs from that of p21(ras)-GppNHp (determined at
      277K) with respect to the degree of order and conformation of the catalytic loop 
      (loop 4 of the switch II region) and the positioning of water molecules around
      the gamma-phosphate group. The changes in the arrangement of water molecules were
      induced by the cryo-temperature technique. CONCLUSIONS: The results shed light on
      the function of Gln61 in the intrinsic GTP hydrolysis reaction. Furthermore, the 
      possibility of a proton shuffling mechanism between two attacking water molecules
      and an oxygen of the gamma-phosphate group can be proposed for the basal GTPase
      mechanism, but arguments are presented that render this protonation mechanism
      unlikely for the GTPase activating protein (GAP)-activated GTPase.
FAU - Scheidig, A J
AU  - Scheidig AJ
AD  - Abteilung fur Physikalische Biochemie, Max-Planck Institute for Molecular
      Physiology, Dortmund, 44227, Germany. scheidig@mpi-dortmund.mpg.de
FAU - Burmester, C
AU  - Burmester C
FAU - Goody, R S
AU  - Goody RS
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Structure
JT  - Structure (London, England : 1993)
JID - 101087697
RN  - 0 (Formycins)
RN  - 0 (Ribonucleotides)
RN  - 059QF0KO0R (Water)
RN  - 16409-13-5 (formycin triphosphate)
RN  - EC 3.6.5.2 (Proto-Oncogene Proteins p21(ras))
SB  - IM
MH  - Crystallography, X-Ray
MH  - Formycins/chemistry/*metabolism
MH  - Hydrolysis
MH  - Molecular Structure
MH  - Proto-Oncogene Proteins p21(ras)/chemistry/*metabolism
MH  - Ribonucleotides/chemistry/*metabolism
MH  - Temperature
MH  - Water
EDAT- 1999/11/27 00:00
MHDA- 1999/11/27 00:01
CRDT- 1999/11/27 00:00
PHST- 1999/11/27 00:00 [pubmed]
PHST- 1999/11/27 00:01 [medline]
PHST- 1999/11/27 00:00 [entrez]
AID - st7b01 [pii]
AID - 10.1016/s0969-2126(00)80021-0 [doi]
PST - ppublish
SO  - Structure. 1999 Nov 15;7(11):1311-24. doi: 10.1016/s0969-2126(00)80021-0.